Diesel exhaust treatement apparatus and methods

ABSTRACT

A diesel exhaust treatment system for treating exhaust gas from a diesel engine comprising at least one diesel oxidation catalyst (DOC), at least one diesel particulate filter (DPF), at least one diesel exhaust fluid mixing chamber and at least one selective catalytic reduction converter (SCR). In one desirable embodiment, two DOCs, two DPFs, two SCRs, and two diesel exhaust fluid mixing chambers are arranged in parallel. The disclosed system is configured to reduce back pressure and increase urea vaporization while effectively using available space and providing improved access to components. The system can be coupled to a vehicle frame rail, such as the frame rail of a heavy duty truck.

CROSS-REFERENCE TO RELATED APPLICATION

In accordance with 37 C.F.R 1.76, a claim of priority is included in anApplication Data Sheet filed concurrently herewith. Accordingly, thepresent invention claims priority as a continuation of U.S. patentapplication Ser. No. 17/032674, entitled “DIESEL EXHAUST TREATEMENTAPPARATUS AND METHODS” filed Sep. 25, 2020.

TECHNICAL FIELD

The technology disclosed herein relates to the treatment of dieselengine exhaust such as diesel engine exhaust from heavy duty truckdiesel engines.

BACKGROUND

Diesel engines are typically subject to exhaust emissions limits set bythe Environmental Protection Agency (EPA). Such emissions standards seekto protect the environment by reducing harmful pollutants being releasedinto the atmosphere by diesel engines. For example, the EPA haspreviously mandated a reduction in allowable levels of particulatematter and nitrogen oxides in exhaust gases. A number of diesel enginesare unable to meet such emission standards. Moreover, it is desirable toreduce pollutants even in the absence of any such government mandatedstandards. Thus, the present disclosure aids diesel engines with adevice and method that reduces the level of pollutants in the exhaust.

More particularly, the disclosure includes a diesel exhaust treatmentsystem and method that treats the diesel exhaust downstream from adiesel engine, before the exhaust is released into the air, that can beemployed in an aftertreatment device. While previous efforts have beenmade to address the treatment of diesel exhaust, the present disclosurereduces back pressure and increases urea vaporization while effectivelyusing available space in such a manner as to provide more ready accessto certain components.

Generally described, untreated diesel exhaust enters the diesel exhaustaftertreatment system through an exhaust gas inlet. The diesel exhaustis first treated by one or more diesel oxidation catalysts (DOCs),wherein hydrocarbons and carbon monoxide are catalytically oxidized toform carbon dioxide and water. The DOC also oxidizes the nitrogen oxide(NO) which helps in passive regeneration as particulate matter oxidizesat a lower temperature in the presence of nitrogen dioxide (NO₂). Theadditional NO₂ also helps with the SCR reaction as SCR reaction is idealwhen the NO:NO₂ ratio is close to 50%. The DOC also helps in oxidizingthe soluble organic fraction (SOF) portion of the soot, which reducesthe particulate matter in the exhaust. The diesel exhaust then passesthrough the one or more diesel particulate filters (DPFs), which filterout particulate matter such as soot and ash. The diesel exhaust thenenters a diesel exhaust fluid mixing chamber, wherein diesel exhaustfluid (DEF) is injected into the system. DEF is a pre-mixed fluidcomposed of about two-thirds pure water and one-third automotive-gradeurea. The DEF hydrolyzes into ammonia gas, which then mixes with thediesel exhaust. The diesel exhaust then enters the selective catalyticreduction converter (SCR), wherein the ammonia gas acts as a catalystand reacts with the nitrogen oxides to form nitrogen and water. Nitrogenand water are natural components of the atmosphere, safe to breath, andare not generally considered to be pollutants.

In one disclosed embodiment, a method of treating exhaust from a dieselengine is disclosed. A stream of untreated exhaust is taken in throughan exhaust gas inlet. The untreated exhaust is split into first andsecond exhaust streams. The first exhaust stream is passed in a firstdirection through a first DOC and then a first DPF, and the secondexhaust stream is passed in the first direction through a second DOC andsecond DPF, thereby removing particulate matter from the exhaust. Oncethe first and second exhaust streams have exited the DPFs, they arecombined into a third exhaust stream. The third exhaust stream is passedin a second direction, opposite to the first direction, through a firstdiesel exhaust fluid mixing chamber, wherein DEF is injected into thesystem. The third exhaust stream then is passed through a second dieselexhaust fluid mixing chamber in a third direction, opposite to thesecond direction. The DEF hydrolyzes into ammonia. After exiting thesecond diesel exhaust fluid mixing chamber, the third exhaust stream issplit into fourth and fifth exhaust streams. The fourth exhaust streamis passed through a first SCR in a fourth direction opposite the thirddirection. The fifth exhaust stream is passed through a second SCR inthe fourth direction. Within the two SCRs, the ammonia reacts with thenitrogen oxides, resulting in the production of nitrogen and water. Oncethe fourth and fifth exhaust streams have passed through the SCRs, theyare combined into a sixth exhaust stream. The sixth exhaust stream issignificantly free of particulate matter and nitrogen oxides, and istherefore safe to be discharged. The sixth exhaust stream passes througha transfer pipe in a fifth direction, opposite the fourth direction, andmay then be discharged from the diesel exhaust treatment system via theexhaust gas outlet.

In accordance with one embodiment, a diesel engine exhaust treatmentsystem is disclosed with at least one DOC, at least one DPF, first andsecond diesel exhaust fluid mixing chambers, at least one SCR, and atleast one transfer pipe. An exhaust gas inlet may be coupled to the atleast one DOC. The at least one DOC is coupled to the at least one DPF.The at least one DPF is coupled to the first diesel exhaust fluid mixingchamber. The first diesel exhaust fluid mixing chamber is coupled to thesecond diesel exhaust fluid mixing chamber. The second diesel exhaustfluid mixing chamber is coupled to the at least one SCR. The at leastone SCR is coupled to the at least one transfer pipe. The at least onetransfer pipe may be coupled to an exhaust outlet.

In accordance with one embodiment, a diesel engine exhaust treatmentsystem is disclosed with a covering for one or more of the exhaustcomponents, which may include at least one DOC and at least one DPF, atleast one diesel exhaust fluid mixing chamber of an extended lengthwherein the exhaust flows in opposite directions while passing throughthe extended mixing chamber, at least one SCR, and at least one transferpipe. In a particularly desirable embodiment, two DOCs, two DPFs, twodiesel exhaust fluid mixing chambers, and one SCR are located behind acovering, while an additional SCR and the transfer pipe are not coveredand are exposed to the atmosphere, thus making them more readilyaccessible.

In accordance with one embodiment, the system can be mounted to avehicle. In a preferred embodiment, the vehicle frame elements extend inthe lengthwise direction of the vehicle. The system may be mounted to aframe element. In another preferred embodiment, the system is mounted toa frame element so that it is positioned beneath the door of thevehicle. The system may further comprise one or more steps to allow adriver to get in and out of the vehicle more easily.

In accordance with one embodiment, a diesel engine exhaust treatmentsystem includes an exhaust gas inlet, at least one DOC, at least oneDPF, first and second diesel exhaust fluid mixing chambers, at least oneSCR, at least one transfer pipe, and an exhaust gas outlet. The dieselexhaust enters the system via the exhaust gas inlet, then flows throughsaid diesel particulate filter in a first direction, then through saidfirst diesel exhaust fluid mixing chamber in a second directiondifferent from said first direction, then through the second dieselexhaust fluid mixing chamber in a third direction opposite to saidsecond direction, then through said one SCR converter in a fourthdirection opposite to said third direction, and then through saidtransfer pipe in a fifth direction opposite said fourth direction to theexhaust gas outlet where the diesel exhaust exits the diesel engineexhaust treatment system.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a schematic illustration of one exemplary embodiment of adiesel engine exhaust treatment system.

FIG. 2 is a perspective view of an exemplary system in accordance withthe present disclosure.

FIG. 3 is a front view of the system of FIG. 2.

FIG. 4 is a side view of the system of FIG. 2.

FIG. 5 is a perspective view of the system of FIG. 2 with certaincomponents to show exemplary components.

FIG. 6 is a perspective view of the system of FIG. 2 with certaincomponents removed to show exemplary components.

FIG. 7 is a perspective view of the system of FIG. 2 with certaincomponents removed or shown in phantom to show exemplary components.

FIG. 8 and FIG. 9 are schematic illustrations of a diesel land vehicle,namely—a diesel truck cab.

FIG. 10 illustrates a diesel engine exhaust treatment system inaccordance with the disclosure located adjacent a door of a diesel truckwith steps included for the purpose of climbing into and out of thetruck.

FIG. 11 is an exemplary embodiment of a diesel engine exhaust treatmentsystem connected to the exhaust gas piping of a vehicle.

FIG. 12 is a side view of an exemplary embodiment.

FIG. 13 is a side view of another exemplary embodiment.

FIG. 14 is a side view of another exemplary embodiment.

FIG. 15 is an exploded view of components of an exemplary embodiment.

DETAILED DESCRIPTION

The disclosure proceeds with reference to a number of illustrativeembodiments, which should not be construed as limiting but instead asbeing exemplary embodiments. The invention includes all novel andnon-obvious methods, features, and systems set forth herein, both aloneand in any and all possible combinations and sub-combinations with eachother.

FIG. 1 is a schematic of an exemplary embodiment of a diesel engineexhaust treatment system 10. The illustrated system 10 as shown includesan exhaust gas inlet 14, an exhaust gas outlet 60, and a number ofexhaust treatment components. The exhaust treatment components enable aflow path between the exhaust gas inlet 14 and exhaust gas outlet 60. Inthe illustrated system 10, certain exhaust treatment components areprotected by a covering 12. The components shown within the covering 12are two DPFs 22B, 26B, two DOCs 22A, 26A, a diesel exhaust fluid mixingchamber 34, and a single SCR 46. The components outside of the covering12 include a single SCR 50 and a transfer pipe 69. It is therefore to beunderstood that the disclosed system 10 provides for a number ofcomponents to be free of the covering 12 and thus more readilyaccessible.

The diesel engine exhaust treatment system 10 is capable of treatingexhaust gas from a diesel engine, including that of a heavy duty truck.In an exemplary method, exhaust gas from a diesel engine is delivered tothe exhaust gas inlet 14. The exhaust gas enters the exhaust gas inlet14 and is then split into two streams of exhaust gas 18, 20. The twostreams 18, 20 then enter the inlets of the two DOCs 22A, 26A, whereinthe hydrocarbons and carbon monoxide are catalytically oxidized to formcarbon dioxide and water. The streams then pass through the DPFs 22B,26B, where particulate matter, such as soot and ash, are trapped andremoved from the exhaust gas streams. In this embodiment, the DOCs 22A,26A and DPFs 22B, 26B are in parallel with each other. In alternativeembodiments, there may be one DPF and one DOC. In other alternativeembodiments, there may be more than two DPFs and two DOCs. However, twoDPFs and two DOCs are sufficient for purposes of the present disclosure.

Diesel particulate filters are used to filter out particulate mattercreated by diesel engines. Diesel engines create particulate matter,such as soot and ash, due to the incomplete combustion of the fuel-airmixture within the engine. In general, older engines are known to createa greater amount of particulate matter. Similarly, two-stroke dieselengines are generally known to produce even more particulate thanfour-stroke diesel engines. A DPF is generally capable of removingapproximately 85% (or more) of the soot and ash from the exhaust gas. Anexample of a DPF is a cordierite wall flow filter, but other forms ofDPFs may be used in the invention. The DPF may preferably be preceded bya diesel oxidation catalyst converter (DOC). A DOC typically containspalladium platinum, and aluminium oxide, all of which catalyticallyoxidize the hydrocarbons and carbon monoxide found within the exhaustgas with oxygen, forming carbon dioxide and water. This process helpseliminate diesel odor and reduce soot. The system in FIG. 1 includes twoDPFs 22B, 26B, each of which is preceded by a DOC 22A, 26A. The use oftwo DPFs and two DOCs is preferred over the use of a single DPF and DOC,as the total cross-sectional area through which the exhaust gas flows isincreased. The increased cross-sectional area, and more specifically theuse of two DPFs and two DOCs, creates less back pressure than if asingle lane of similar volume was used in the diesel engine exhausttreatment system 10.

Two streams of filtered exhaust 24, 28 exit the DPFs 22B, 26B through anoutlet 22C, 26C and thereafter combine to form a single stream 30. Thesingle exhaust stream 30 then enters an inlet 32 of the diesel exhaustfluid mixing chamber 34. The diesel exhaust fluid mixing chamber 34includes an injection system that injects a urea solution, also referredto as diesel exhaust fluid (DEF), into the exhaust. A common ureasolution is composed of around ⅓ urea and ⅔ water. The urea solution isstored in a storage unit 36, such as a urea solution tank. The storageunit 36 is in fluid connection with an injector 35, which is connectedto the inside of the diesel exhaust fluid mixing chamber 34. In apreferred embodiment, the injection point of the urea solution is at theupstream end of the diesel exhaust fluid mixing chamber 34. Uponinjection, the urea undergoes thermal decomposition and hydrolysis,resulting in ammonia. In alternative embodiments, the injector maysupply ammonia to the exhaust stream. However, the urea solution ispreferable as it is safer to store and is commonly available at truckstops and gas stations. The amount of urea solution or ammonia can becontrolled via sensors (not shown) that determine the nitrous oxidelevels in the exhaust stream after exiting the DPFs 22B, 26B, but beforeentering the diesel exhaust fluid mixing chamber 34. The urea solutionor ammonia mixes with the exhaust, becoming generally evenlydistributed. In FIG. 1, there is a single diesel exhaust fluid mixingchamber 34, that extends from one end of the system to the opposite end,and then doubles back to the first end. In another embodiment, there maybe two diesel exhaust fluid mixing chambers where the exhaust streamflows from a first diesel exhaust fluid mixing chamber to a seconddiesel exhaust fluid mixing chamber. The use of two diesel exhaust fluidmixing chambers or a single diesel exhaust fluid mixing chamber thatdoubles back on itself allows for increased urea vaporization comparedto diesel exhaust fluid mixing chambers of shorter lengths.

The stream of exhaust gas containing ammonia 40 exits the diesel exhaustfluid mixing chamber 34 via an outlet 38 and splits into two streams 42,44. The two streams 42, 44 enter into two SCRs 46, 50 via SCR inlets 45,49. An SCR is known to those of ordinary skill to convert nitrogenoxides into diatomic nitrogen and water. An SCR utilizes a catalystwhich reacts with the nitrogen oxides and ammonia within the exhauststream as the exhaust streams 42, 44 pass through the catalyst chamber46, 50. SCR catalysts are generally comprised of a substrate and a washcoat. The substrate is composed of cordierite. The wash coat is anon-active carrier and active catalytic components. The non-activecarrier is often made from ceramic materials such as titanium oxide (orevident). The active catalytic components are typically a preciousmetal, zeolites, or an oxide of a base metal, such as vanadium,molybdenum and tungsten. The SCR catalysts are generally shaped as ahoneycomb or a plate, but for automotive applications the use ofextruded honeycomb components is preferred. In FIG. 1, two SCRs 46, 50are shown in parallel. In alternative embodiments, additional SCRs maybe utilized, but two SCRs is generally sufficient to reduce pollutantsbelow EPA mandated limits. The use of two SCRs is preferred over the useof a single SCR, as the total cross-sectional area through which theexhaust gas flows is increased. The increased cross-sectional areareduces back pressure through the diesel engine exhaust treatmentsystem, maintaining increased fuel efficiency.

In FIG. 1, the illustrated embodiment has a partial covering 12 withfirst and second end walls 15, 17, a top wall 19, and a bottom wall 21.In the embodiment shown, two DOCs 22A, 26A, two DPFs 22B, 26B, onediesel exhaust fluid mixing chambers 34, and one SCR 46 are covered bythe partial covering 12, while one SCR 50 and the transfer pipe 69 arenot. The SCR 50 and transfer pipe 69 are located outside of the covering12 and arranged in parallel with the rest of the components.

In FIG. 1, the illustrated embodiment of the diesel engine exhausttreatment system 10 has an exhaust flow path that operates in fivedirections. In the system shown, the exhaust gas enters the systemthrough the exhaust gas inlet 14 adjacent to the first end wall 15. Theexhaust gas is split into two streams 18, 20, which both flow throughthe DOCs 22A, 26A and then the DPFs 22B, 26B in a first direction. Uponexit, the two streams 18, 20 have been treated by the DOCs 22A, 26A andDPFs 22B, 26B and thus become streams 24, 28, which combine to formstream 30, which then flows into the diesel exhaust fluid mixing chamber34. The stream 30 flows through the mixing chamber 34 in a seconddirection, opposite the first direction, before turning back and flowingin a third direction, opposite the second direction. In alternativeembodiments that utilize two diesel exhaust fluid mixing chambers, theexhaust stream would flow through a first mixing chamber in a seconddirection, opposite the first direction, and then would flow through thesecond mixing chamber in a third direction, opposite the seconddirection. Upon exiting from the mixing chamber 34, the stream 40 splitsinto streams 42, 44 which pass through the SCRs 46, 50 in a fourthdirection, opposite the third direction. Upon exiting from theirrespective SCRs 46, 50, the streams 48, 52 combine into a stream 53which passes through a transfer pipe 69 in a fifth direction, oppositethe fourth direction, and exits the exhaust gas outlet 60.

In order to maintain suitable temperatures throughout the diesel engineexhaust treatment system 10 and the diesel treatment components withinthe system, insulating matting can be utilized to aid in containing heatwithin the system and the components, resulting in higher internaltemperatures, for example, within the SCRs 46, 50, DOCs 22A, 26A andDPFs 22B, 26B, which can increase their effectiveness in removingpollutants from the exhaust. The covering 12 can aid in retaining heat,but only for components that are sufficiently shielded. The SCR 50 isnot shielded, and thus the SCR 50 is preferably insulated with mattingor an alternative insulating material. This allows for minimal heat lossin the externally located SCR 50, therefore maintaining high efficiencyfor the internal catalytic reduction process. If more than one SCR isexposed to the atmosphere, or an alternative component such as a DOC orDPF, such other exposed components may also be insulated with matting oran alternative insulating material.

Because the SCR 50 is not covered, this allows for easier access to theSCR 50 for inspection and replacement of the SCR catalyst. SCR catalystsgenerally have a finite life due to their porous construction, as theybecome plugged or contaminated from urea or other unwanted deposits suchas biuret. For example, ammonia sulfur compounds, ammonium bisulfate,and silicon compounds, all of which may potentially plug an SCRcatalyst. Additionally, exhaust gas may contain certain poisons or otherunwanted substances which will destroy the chemistry of the catalyst andrender the SCR ineffective at reducing nitrogen oxide, and potentiallycreating more nitrogen oxide through the oxidation of ammonia. Thesesubstances may include, but are not limited to, sulfur, halogens,alkaline metals, arsenic, phosphorus, antimony, and chrome. By exposingat least one of the SCRs 50 so that it is not covered, its SCR catalystcan be more easily accessed for inspection, and the inspected status ofthe externally located SCR catalyst is informative of the status of theSCR 46 located within the partial covering 12. Therefore, the status ofboth SCR catalysts may be more easily determined.

FIG. 2 is an exemplary embodiment of the diesel engine exhaust treatmentsystem 10 described in FIG. 1. Certain elements of the system 10 are notshown in FIG. 2 in order to illustrate the internal components and theexhaust flow path. FIG. 2 illustrates the flow path of the exhaust gasthrough the system 10. The exhaust gas enters the system 10 via theexhaust gas inlet 14, and then enters a first stream splitting chamber74, where the exhaust gas is split into two streams 18, 20. The twostreams 18, 20 flow through the DOCs 22A, 26A, respectively, and thenDPFs 22B, 26B, respectively, in a first direction. The streams 24, 28enter a first common chamber 72 where the streams 24, 28 combine intostream 30, which then enters the diesel exhaust fluid mixing chamber 34,wherein the exhaust gas flows in a second direction and then turns backand returns in a third direction. The exhaust gas exits the dieselexhaust fluid mixing chamber 34 in a stream 40, which enters the secondstream splitting chamber 75 where it then splits into streams 42, 44,which enter the two SCRs 46, 50 and flow in a fourth direction. Theexhaust gas exits the SCRs 46, 50 in two streams 48, 52 and combinesinto a stream 53 in a second common chamber 73 and then enters thetransfer pipe 69, wherein the exhaust gas flows in a fifth direction.The treated exhaust gas 52 exits through the exhaust gas outlet 60.

In alternative embodiments, the streams may not be combined prior toentering the diesel exhaust fluid mixing chamber 34. Instead, each DPF22B, 26B has a separate fluid connection from its DPF outlet to an inletof the diesel exhaust fluid mixing chamber 34. The two streams maycombine in the diesel exhaust fluid mixing chamber 34. Similarly,alternative embodiments may have two transfer pipes, and therefore thetwo streams do not recombine in a second common chamber after exitingthe SCRs 46, 50, but instead would recombine when they flow through theexhaust gas outlet 60 and exit the system 10.

In FIGS. 3-6, an exemplary embodiment of the diesel engine exhausttreatment system 10 is shown. FIG. 3 is a view of the system 10, andillustrates the second SCR 50 and transfer pipe 69 as being locatedexternal to the covering 12. The covering 12 is shown to be comprised oftwo end walls 15, 17, a top wall 19, and a bottom wall 21 that areconfigured to protect the components covered thereby. It will beappreciated that the end walls serve as the sides of the disclosedsystem 10.

FIG. 3 is a front view of an exemplary embodiment of the system 10 thatshows the partial covering 12 and an exposed SCR 50. The covering 12extends partially across the system 10, but does not cover the SCR 50 orthe transfer pipe 69. It is to be understood that the exposed SCR 50sits and extends further in the direction of the outlet 60 than othercomponents, which may facilitate securing of the system in a convenientlocation beneath the door of a diesel truck cab. FIG. 3 also shows endwalls 15 and 17.

FIG. 4 is an end view of the diesel engine exhaust treatment system 10shown in FIGS. 2-3. The first end wall 15 covers the exhaust treatmentcomponents except for the exposed SCR 50 and transfer pipe 69. Amounting bracket 70, is coupled to the first end wall 15. The mountingbracket 70 attaches to a frame rail of the vehicle. In the embodimentillustrated in FIG. 4, a frame element may be positioned above the SCR50 located external to the covering 12 of the system 10. In alternativeembodiments, the frame rail would not be positioned above any portion ofthe system 10.

FIGS. 5-6 illustrate the same exemplary embodiment shown in FIGS. 2-4.In FIG. 5, the top 19, bottom 21, and end (or side) walls 15, 17 havebeen removed in order to show the components that are within thecovering 12. In the shown embodiment, the enclosed components includetwo DOCs 22A, 26A, two DPFs 22B, 26B, a diesel exhaust fluid mixingchambers 34, and one SCR 46. Additionally shown is the second SCR 50,which is not covered by the covering 12. The person of ordinary skillwill recognize that all of the components are arranged in parallel. Afirst common chamber 72 is shown in fluid connection with the two DPFs22B, 26B and the inlet of the diesel exhaust fluid mixing chamber 34.The first common chamber 72 allows the two streams of exhaust gas 24, 28exiting the two DPFs 22B, 26B to combine into a single stream of exhaustgas 30 before entering the diesel exhaust fluid mixing chamber 34. Asecond common chamber 73, analogous to the first chamber 72 fluidlyconnects the two SCRs 46, 50 with the transfer pipe 69, allowing the twostreams exiting the two SCRs 46, 50 to combine into a stream 52 beforeentering the transfer pipe 69.

In FIG. 6, the stream splitting chamber 74 is shown fluidly connectingthe exhaust gas inlet 14 with the two DOCs 22A, 26A. The single streamof exhaust gas from the exhaust gas inlet 14 flows into the first streamsplitting chamber 74, where the exhaust gas splits into two streams 18,20 and each newly formed stream flows into one of the DOCs 22A, 26A. Asecond stream splitting chamber 75, analogous to the first streamsplitting chamber 74 is not shown, but it fluidly connects the outlet ofthe diesel exhaust fluid mixing chamber 34 with the inlet of the twoSCRs 46, 50, wherein the single stream of exhaust gas that exits themixing chamber 34 splits into two streams 42, 44 that flow into the SCRs46, 50.

In FIG. 7, the DOCs 22A, 26A and DPFs 22B, 26B have been removed inorder to show the arrangement of the two SCRs 46, 50. One SCR 46 islocated within the covering 12, while the other SCR 50 is locatedoutside of the covering 12, allowing for easier and quicker access inorder to inspect the SCR catalyst within the SCR 50. The mixing chamber34 is further shown as in fluid communications with the SCRs 46, 50 (50is shown in phantom) as the stream 40 exits the mixing chamber andsplits into streams 42, 44 for delivery to their respective SCRs.

FIGS. 8-10 illustrate a truck 100 for use with a trailer (not shown).The truck includes a diesel engine 102, and frame elements extendinglengthwise from generally the front of the truck 108 to the back of thetruck 110. The frame elements include rails 104, 106 that are preferablyparallel to each other. Alternative embodiments can have three or moreframe rails, and/or the frame rails may not be in parallel with eachother. The diesel engine exhaust treatment system 10 is coupled to aframe rail, preferably the frame rail nearest the driver-side door. Thediesel engine exhaust treatment system 10 and frame rail are coupled toeach other via the mounting bracket 70, such as mounting brackets thatattach to the frame rail and to the covering 12 of the system 10 in aconventional manner. In the embodiment shown in FIGS. 8-10, the exposedSCR 50 not behind the covering 12 and is positioned partially under theframe rail 104 such that a portion of the covering 12 is positionedoutside of the frame rail's 104 vertical plane, towards the side 124 ofthe truck 100. An engine exhaust outlet pipe 116 from the diesel engine102 is attached to the exhaust gas inlet 14, providing fluid connectionbetween the diesel engine's exhaust outlet 118 and the diesel engineexhaust treatment system 10. Once the exhaust gas flows from the dieselengine 102 into the diesel engine exhaust treatment system 10, theexhaust gas is treated by at least one DOC, at least one DPF, at leastone diesel fluid mixing chamber, and at least one SCR before exiting thesystem 10. It is preferred that the exhaust gas is treated by a system10 as described in FIG. 1. The treated exhaust gas exits the dieselengine exhaust treatment system 10 through the exhaust gas outlet 60,which is coupled to an exhaust pipe 120. The exhaust pipe 120 expels thetreated exhaust gas into the atmosphere.

FIGS. 9-10 illustrate an embodiment of the diesel engine exhausttreatment system 10 as mounted on the truck 100. In this embodiment, thediesel engine exhaust treatment system 10 is positioned to the rear ofthe truck cab door 122. In alternative embodiments, the system 10 ispositioned directly beneath the truck cab door 122. FIG. 10 is anillustrated view of the truck 100 and diesel engine exhaust treatmentsystem 10 with portions of the truck 100 removed in order to see thesystem 10. Exhaust gas from the diesel engine 102 flows into the dieselengine exhaust treatment system 10 via an engine exhaust outlet pipe 116connected to the exhaust gas inlet 14. The exhaust gas passes throughthe various treatment components within the system 10, as for exampledescribed in reference FIG. 1. The treated exhaust gas exits the system10 via the exhaust gas outlet 60 which is connected to an exhaust pipe120. The exhaust pipe 120 expels the treated exhaust gas into theatmosphere.

FIG. 11 illustrates an embodiment of the diesel engine exhaust treatmentsystem 10 and its connection to the truck's 100 exhaust system. Theexhaust gas inlet 14 is coupled to the engine exhaust outlet pipe 116 ina conventional manner. The exhaust gas outlet 60 is coupled to theexhaust pipe 120 in a conventional manner. In the embodiment shown, theexhaust gas inlet 14 is located towards the end of the system 10 locatednearest the front of the truck 108, while the exhaust gas outlet 60 islocated on the opposite end of the system 10. In alternativeembodiments, the exhaust gas inlet 14 and outlet 60 may be located onthe same end of the system 10. The person of ordinary skill willappreciate that such alternative embodiments would not require atransfer pipe 69.

FIG. 12 is a schematic of a cross-section of the exemplary diesel engineexhaust treatment system 10 illustrated in FIGS. 2-7. The DOCs 22A, 26A,DPFs 22B, 26B, diesel exhaust fluid mixing chamber 34, SCRs 46, 50,transfer pipe 69, and partial covering 12 are shown in the samepositions as they are in FIGS. 2-7. The positioning of the componentsallows for a compact system. For example, in one embodiment, the system10 may have a height of 837 millimeters and width of 818.5 millimeters.The overall length of this exemplary system 10 may be 902 millimeters.Alternative embodiments may have different dimensions, based on the useof more or less exhaust gas treatment components, or components withdifferent cross-sectional areas or lengths. The use of insulatingmaterials will increase the overall dimensions of the system 10.

FIGS. 13 and 14 are similar cross-section views that illustratealternative arrangements of DOCs 22A, 26A, DPFs 22B, 26B and SCRs 46,50, as compared to the arrangement shown in FIG. 12. In alternativeembodiments, the diesel exhaust fluid mixing chamber 34 may bepositioned differently. As shown, these figures illustrate the DOCs 22A,26A, the DPFs 22B, 26B, the mixing chamber 34, the SCRs 46, 50 and thetransfer pipe 69. As described herein, these components cooperate totreat the diesel exhaust and remove pollutants therefrom. FIG. 13illustrates an embodiment of the system 10 where the two SCRs 46, 50 arepositioned adjacent to the top wall 19, above the two DOCs 22A, 26A, twoDPFs 22B, 26B, and the diesel exhaust fluid mixing chamber 34. One DOC22A, one DPF 22B, and the transfer pipe 69 are located external to thecovering 12, while the other components are within the covering 12. FIG.14 illustrates an additional embodiment of the system 10 where one SCR50, one DOC 22A, and one DPF 22B are positioned adjacent to the top wall19, above the SCR 46, DOC 26A, DPF 26B, and the diesel fluid exhaustmixing chamber 34. One SCR 46 and the transfer pipe 69 are locatedexternal to the covering 12, while the other components are within thecovering 12.

The disclosed system 10 provides for various arrangements of the exhausttreatment components, allowing for the various components to be locatedexternally to the covering 12 and therefore readily accessible. A personof ordinary skill in the art will appreciate that the variousalternative arrangements of the exhaust treatment components willnecessitate corresponding alternative arrangements of the streamsplitting chambers 72, 74 and common chambers 73, 75. It is to beunderstood that the arrangement and operation of these componentseffectively utilize available space for placement on a diesel truck andto process the diesel exhaust in a manner that reduces back pressure.More particularly, the components shown are preferably provided inparallel such that the effective back pressure may be less than whatcould typically be experienced by catalysts of the same volume in asingle lane arrangement. Further, the disclosed system 10 is capable ofmaintaining an effective flow of exhaust gas and ammonia and/or ureafluid even after the exhaust flow is split into streams 42, 44 beforeentering the SCRs 46, 50. It will further be understood by the person ofordinary skill that added length of the mixing chamber 34 (as, forexample, by a two-fold extension as the exhaust travels in the secondand third directions) allows for enhanced urea vaporization.

FIG. 15 is an exploded view of the exemplary embodiment of the dieselengine exhaust treatment system 10 illustrated in FIGS. 2-7. Thecomponents of the system 10 are shown detached from one another, inorder to fully illustrate each component and how they fit with eachother. The first stream splitting chamber 74 has an opening where theexhaust gas inlet 14 attaches to allow for exhaust gas to flow into thechamber 74. The two DOCs 22A, 26A and a first component plate 80, whichhas two holes 81, 83 for engaging the DOCs 22A, 26A, are thus in fluidcommunication. A first component plate 80 engages both the two DOCs 22A,26A and the first stream splitting chamber 74 to allow for such fluidcommunication. The first component plate 80 further fixes the secondcommon chamber 73 with the enclosed SCR 46 to allow for fluidcommunication, and further aids in fixing the diesel exhaust fluidmixing chamber 34. The externally located SCR 50 is fixed directly tothe second common chamber 73. A second component plate 82 fixes the twoDPFs 22B, 26B to the first common chamber 72, thereby allowing for fluidcommunication between the DPFs and ultimately, the SCRs 46, 50. Thesecond component plate 82 further fixes the diesel exhaust fluid mixingchamber 34 to both the first common chamber 72 and the second streamsplitting chamber 75 to allow for a single exhaust gas stream to flowfrom the first common chamber 72 into the mixing chamber 34. That streamthen exits the mixing chamber 34 into the second stream splittingchamber 75. The second component plate 82 further fixes the SCR 46 withthe second stream splitting chamber 75 to allow for fluid communication.The external SCR 50 is fixed directly to the second stream splittingchamber 75 with no intermediary component plate. The partial covering 12(which can also act as a heat shield) protects certain exhaust treatmentcomponents, except for a single SCR 50 and transfer pipe 69. Thetransfer pipe 69 is fixed to the second common chamber 73 and theexhaust gas outlet 60, allowing for treated exhaust gas to flow from thesecond common chamber 73 through the transfer pipe 69 and out throughthe exhaust gas outlet 60. A plate 86 may be provided to shield theexposed SCR 50 and transfer pipe 69 from road debris or other foreignobjects 9 as the diesel truck travels a roadway.

1. A diesel engine exhaust treatment system for treating exhaust gasesfrom a diesel engine of a land vehicle, the diesel engine exhausttreatment system comprising first and second end portions, an exhaustgas inlet, an exhaust gas outlet, and aftertreatment components fortreating a flow of diesel exhaust, the aftertreatment componentscomprising: a. At least one diesel oxidation catalyst, each said dieseloxidation catalyst comprising a diesel oxidation catalyst inlet coupledto said exhaust gas inlet and a diesel oxidation catalyst outlet; b. Atleast one diesel particulate filter, each said diesel particulate filtercomprising a diesel particulate filter inlet coupled to said dieseloxidation catalyst outlet and a diesel particulate outlet; c. At leastone diesel exhaust fluid mixing chamber, said diesel exhaust fluidmixing chamber comprising a mixing chamber inlet coupled to each of thediesel particulate filter outlets and a mixing chamber outlet; d. Atleast one exposed selective catalytic reduction (SCR) converter, eachsaid SCR converter comprising an SCR inlet coupled to said second mixingchamber outlet and an SCR outlet; and e. At least one transfer pipe,each transfer pipe comprising a transfer pipe inlet coupled to each ofsaid SCR outlets and a transfer pipe outlet coupled to said exhaust gasoutlet, wherein the aftertreatment components extend in a lengthwisedirection from the first end portion to the second end portion.
 2. Thediesel engine exhaust treatment system for treating exhaust gases from adiesel engine of a land vehicle of claim 1 further comprising a secondexposed selective catalytic reduction (SCR) converter, each said SCRconverter comprising an SCR inlet coupled to said second mixing chamberoutlet and an SCR outlet, wherein said second exposed SCR converter alsoextends in a lengthwise manner from the first end portion to the secondend portion.
 3. The diesel engine exhaust treatment system for treatingexhaust gases from a diesel engine. of a land vehicle of claim 2 wheresaid one diesel exhaust fluid mixing chamber comprises an elongatedchamber that passes exhaust in a first direction and then in seconddirection before delivery of said exhaust to an SCR so as to increasevaporization of the urea.